United States Patent (19) [11] 3,871,900 Hayashi et al. (45) Mar. 18, 1975

54 RECORDING SHEET 3,346,571 10/1967 Spatz et al...... 1 7/36.2 X 3,632,376 1 / 1972 Newman...... l 7/36. X 75 Inventors: Takao Hayashi; Hajime Kato, both 3,664,858 5/1972 Huffman...... | 17/36.8 of Fujinomiya-shi, Shizuoka; 3,767,449 10/1973 Hayashi et al...... 17/36.8 X Sadao Ishige, Minami Ashigara-shi, 3,769,062 10/1973 Ishige et al...... 7/36.2 Kanagawa, all of Japan 3,772,052. 1 1/1973 Kimura et al...... 117/36.2 (73) Assignee: Fuji Photo Film Co., Ltd., Minami Ashigara-shi, Kanagawa, Japan Primary Examiner-Thomas J. Herbert, Jr. Attorney, Agent, or Firm-Sughrue, Rothwell, Mion, (22 Filed: July 24, 1973 Zinn & Macpeak 21 Appl. No.: 382,224 57 ABSTRACT (30) Foreign Application Priority Data A recording sheet comprising a support having July 28, 1972 Japan...... 47.75758 thereon a color developer layer capable of reacting with a color former to form color images, said color 52 U.S. Cl...... 117/36.8, 117/36.2 developer layer containing (l) a metal compound of (51 Int. Cl...... B41m 5100 an aromatic carboxylic acid and (2) at least one mem 58 Field of Search...... 117/36.2, 36.8 ber selected from the group consisting of ethers and (56. References Cited alcohols. UNITED STATES PATENTS 19 Claims, No Drawings 2,663,653 21 1953 Zimmerman...... 117.136.2 3,871,900 1 2 RECORDING SHEET Of these, a metal compound of an aromatic carbox ylic acid is particularly effective as a color developer. BACKGROUND OF THE INVENTION That is, a color developer sheet containing as a color 1. FIELD OF THE INVENTION developer a metal compound of an aromatic carboxylic The present invention relates to a recording sheet, acid has the following excellent properties in compari and more particularly to a recording sheet containing son with conventional color developer sheets. an improved color developer. l. Even when left in the air, reduction in color 2. DESCRIPTION OF THE PRIOR ART developing ability with the passage of time is small. Recording sheets utilizing a color reaction of an al 2. By using an aromatic carboxylic acid difficult to most colorless organic compound (hereinafter referred 10 dissolve in water, disappearance or reduction in to as a "color former') such as Malachite green lac density can be avoided even when the color former tone, benzoyleucomethylene blue, crystal violet ace on the color developer sheet is wet with water. tone, Rhodamine B lactam, 3-dialkylamino-7- 3. The light fastness of the colored image on the color dialkylaminofluoran and 3-methyl-2,2'-spirobi (ben developer sheet is excellent. Zof chromene), and an adsorbent or reactive material 15 4. Since sufficient color-developing ability can be ob (hereinafter referred to as a “color developer') capa tained using a small coating amount, workability in ble of forming a color when contacted with the color coating is very good. former are well known. As is described above the properties of the recording As the recording sheets practically using the phe sheet and the various problems encountered in the pro 20 duction thereof have been improved considerably by nomenon, there are a pressure-sensitive recording using a metal compound of an aromatic carboxylic acid sheet (see, for example, U.S. Pat. Nos. 2,505,470; as a color developer instead of the conventional color 2,505,489; 2,550,471; 2,548,366; 2,730,456; developers. 2,730,457; 3,418,250, etc.) and a heat-sensitive re However, there remain the disadvantages that, in the cording sheet (see, for example, Japanese Patent Publi 25 production of a metal compound of an aromatic car cation Number 460/68; U.S. Pat. No. 2,939,009, boxylic acid, the viscosity of the prepared (coating) so etc.). Further, a printing method is known wherein an lution increases and the particle size of the metal com ink containing the color former is applied to the color pound becomes coarse thereupon. Therefore, it is diffi developer sheet through a medium such as a stencil cult to prepare a stable coating solution and, unless the (see German Patent OLS No. 1,939,62, etc.). 30 particle size of the metal compound is made fine by In many cases, the above mentioned phenomenon of means of a ball mill or sand mill, there is room for im the color reaction between the color former and the provement in the color-developing ability and film sur color developer requires physical conditions such as face strength of the coated layer. pressure with a pen or with a key of a typewriter, heat, A primary object of the present invention is to im Ctc. 35 prove the color-developing ability of a color developer As the most representative embodiment of the re sheet containing a metal compound of an aromatic car cording sheets, there is illustrated a pressure-sensitive boxylic acid. copying paper. A pressure-sensitive copying paper may Another object of the present invention is to simplify be obtained by dissolving a color former in a solvent the steps for preparing a coating solution containing an such as chlorinated paraffin, alkylnaphthalene, alkyl 40 aromatic carboxylic acid. ated diphenylethane, alkylated diphenylmethane, or Further object of the present invention is to improve the like, dispersing the resulting solution in a binder or the coating characteristics of the coating solution con microencapsulating the solution, and then the coating taining an aromatic carboxylic acid. on a support such as paper, plastic film, etc. Still a further object of the present invention is to A heat-sensitive recording sheet may be obtained by 45 provide a color developer having the above-described coating a color former on a support together with a advantages. thermofusible material such as acetanilide. As used Still a further object of the present invention is to herein, the term "thermofusible material' means a ma provide a recording sheet having the above-described terial which is melted on heating to dissolve the color advantages. former. 50 In general, the color former and color developer may SUMMARY OF THE INVENTION be coated on the same surface or opposite surfaces of As a result of various investigations, it has been found a support, or on different supports. Also, the color de that the addition of at least one member selected from veloper may be coated on or impregnated into a sup the ethers and alcohols to a color-developing layer con port as an ink. 55 taining a metal compound of an aromatic carboxylic As the above-described color developer, clays such acid achieves the above-described objects. as acid clay, activated clay, attapulgite, zeolite, benton ite, etc.; organic acids such as succinic acid, tannic DETAILED DESCRIPTION OF THE INVENTION acid, gallic acid or phenol compounds, and acidic poly The ethers suitable for use in this invention can be mers such as phenol resins are known. Furthermore, a 60 represented by the formula, mixture of an aromatic carboxylic acid and a metal compound; a metal compound of a polymer of an aro ROX matic carboxylic acid having at least one hydroxy wherein X is -(CH2)OR', -(CH2)OH, - (CH group and an aldehyde; a metal compound of an aro ),OH, - (CH)OR', an alkyl group (preferably, matic carboxylic acid; a metal compound of a phenol 65 having up to 18 carbon atoms) or an alkenyl group compound having a pKa of not more than 8; and the (preferably, having up to 18 carbon atoms), R is an like, are effective as a color developer. alkyl group (preferably, having up to 10 carbon 3,871,900 3 4 atoms), an aryl group (preferably, having up to 10 car water-soluble metal salt may be reacted with each bon atoms) or an alkenyl group (preferably, having up other in optional porportions, but preferably, they are to 10 carbon atoms), R' and R' each is an alkyl group reacted in gram equivalent amounts. (preferably, having up to 18 carbon atoms), an aryl The metal compound of an aromatic carboxylic acid group (preferably, having up to 18 carbon atoms) or an 5 is a salt of such an acid such as a zinc, tin, aluminum, alkenyl group (preferably, having up to 18 carbon nickel, magnesium or calcium salt of an aromatic car atoms), p is an integer of 1 to 20 (preferably, 2 or 3), boxylic acid, and these salts can be obtained easily by and q is an integer of 2 to 30. stirring an aromatic carboxylic acid or an alkali metal As specific examples of the ethers, ethers such as eth salt thereof with a metal hdyroxide, sulfate or nitrate in ylene glycol monomethyl ether, diethylene glycol O the presence of an alkali. In this procedure, the pH monomethyl ether, diethylene glycol mono-n-butyl value, temperature and pressure are not critical. ether, ethylene glycol monophenyl ether, diethylene The aromatic carboxylic acid is preferably repre glycol dimethyl ether, 3-methoxybutyl acetate, ethyl ene glycol monoethyl ether, ethylene glycol diethyl sented by the formula: ether, diethylene glycol acetate monoethyl ether, ethyl 15 COOH COOH ene glycol diphenyl ether, ethylene glycol dimethyl ether, ethylene glycol monobutyl ether, ethylene glycol monopropyl ether, ethylene glycol monobenzyl ether, ethylene glycol monooctyl ether, ethylene glycol Or monododecyl ether, diethylene glycol monoethyl ether, 2O (R), (R) dipropylene glycol monomethyl ether, polyoxyethylene cetyl alcohol ether, polyoxyethylene oleyl alcohol ether, polyoxyethylene stearyl alcohol ether, polyoxy wherein R may be the same or different and represents ethylene lauryl alcohol ether, polyoxethylene octyl al a hydrogen atom, a hydroxy group, a halogen atom cohol ether, polyoxyethylene butyl alcohol ether, poly 25 oxyethylene nonyphenol ether, etc are suitable. such as chlorine, a nitro group, an alkyl group having The alcohols are preferably aliphatic alcohols having 1 to 10 carbon atoms (preferably 3 to 6 carbon atoms), 1 to 18 carbon atoms, although other alcohols can be of which the total carbon atoms are less than 13, an aryl employed. Specific examples are alcohols such as n group such as phenyl group, an arylamino group such butyl alcohol, n-amyl alcohol, n-hexyl alcohol, n-heptyl as anilino group, and an alicyclic group such as hexyl alcohol, n-octyl alcohol, n-nonyl alcohol, n-decyl alco group, m is an integer of 0 to 7 and n is an integer of hol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stea 0 to 5, and the aromatic carboxylic acid may be dimer ry alcohol, isobutyl alcohol, sec-butyl alcohol, isoamyl ized through the substituent R as a methylene group. alcohol, tert-butyl alcohol, sec-butyl carbinol, diethyl More preferable compounds are those represented carbinol, 1-hexanol, 2-hexanol, 3-hexanol, cyclohexa 35 by the formula, nol, 3-methyl-1-pentanol, 4-methyl-2-hexanol, allyl al COOH cohol, trans-crotyl alcohol, ciscrotyl alcohol, 2-methyl-3-buten-1-ol, o-tolyl carbinol, m-tolyl carbi OH nol, p-tolyl carbinol, benzyl alcohol, etc., are suitable. Mixtures of ethers and alcohols can be used where de 40 sired. (R) Of the ethers to be used in the invention, glycol ethers are particularly desirable and, of the alcohols, alcohols having 4 or more carbon atoms are particu 45 COOH larly preferable. That is, when a glycol ether or an alco hol having 4 or more carbon atoms is used, the color developing ability is markedly improved and, when they are used in combination, the color-developing

No. Kind Fther or Amount Color-developing Color-develop Alcohol Added Ability Toward ing Ability Crystal Violet Toward 3-N,N- lactone diethylanninc-6, 8-diethylfluoran

Com parative 0.73 ()6(2 Ex 2 Ex. Butanol 15 g 0.813 0.7 ( 3 Ex Diethylene Glycol 20 g (),935 ().757 Monobuty Ether 4. Ex. Ethylene Glycol 30 g O952 ().783 Monobutyl Y Ether S Ex. 3-Methoxy buty 20 g O894 ().7() Acctatic 6 Ex Diethylene Glycol 20 g ().855 Of)8 Monomethyl Ether *In the examples the color developing ability was determined by an optical densittincter (reflectance at 400 to 700 m). The numerical value shows the color cliensity at maximum.

9. Subsequently, the system was heated for 20 minutes EXAMPLE 2 under stirring to raise the liquid temperature to 50°C. 0. Mol of 5-tert-butylsalicylic acid was dissolved in The thus obtained microcapsule dispersion was ad 35 a mixture of 0.1 mol of sodium hydroxide and 300 ml justed to 30°C and applied to a 40 g/m paper in an of water. To this solution were added 30 g of a 10% pol amount of 6 g/m' based on the amount of solid ingredi yvinyl alcohol (as described in Example 1) acqueous so ents followed by drying. lution, 10 g of diethylene glycol monobutyl ether and The following examples and comparative examples 10g of talc. Then, a solution prepared by dissolving 0.7 were conducted using a sheet coated with microcap 40 mol of zinc chloride in 100 cc of water and a solution sules containing crystal violet lactone or 3-N,N- prepared by dissolving 0.3 mol of nickel sulfate in 300 diethylamino-7-N,N-dibenzylaminofluoran. cc of water were gradually added thereto under stir ring. To this solution was added 20 g of a styrene methyl methacrylate (1:1 molar ratio) copolymer latex EXAMPLE 1. 45 to prepare a coating solution. The resulting solution 0.1 Mol of 5-tert-butylsalicylic acid was dissolved in was applied to a 50 g/m paper in an amount of 3 g/m. a mixture of 0.1 mol of sodium hydroxide and 300 ml based on the solid ingredients followed by drying. The of water. To this solution were added 30 g of a 10% pol viscosity of the solution was low, and the coating char acteristics of the solution were good. yvinyl alcohol (polymerization degree: about 500, sa 50 ponification degree: about 87%) aqueous solution and COMPARATIVE EXAMPLE 2 an ether or alcohol as listed in the following table. Then, a solution prepared by dissolving 0.1 mol of zinc O. l Mol of 5-tert-butylsalicylic acid was dissolved in chloride in 100 cc of water was gradually added thereto 0.1 mol of caustic soda and 300 ml of water. To this so under stirring. The resulting coating solution was lution was added 30 g of a 10% polyvinyl alcohol aque 55 ous Solution. Then, a solution prepared by dissolving coated on a 50 g/m paper in an amount of 2 g/m' based 0.7 mol of zinc chloride in 700 cc of water and a solu on the solid ingredients followed by drying. The viscos tion prepared by dissolving in 300 cc of water ().3 mol ity of the coating solution was low, and the coating of nickel sulfate were gradually added thereto under characteristics of the solution were good. stirring. To this solution was added 20 g of a styrene 60 methyl methacrylate copolymer latex to prepare a coating solution. COMPARATIVE EXAMPLE Since the viscosity of the coating solution increased, 0.1 Mol of 5-tert-butylsalicylic acid was dissolved in many bubbles were contained therein, and since the a mixture of 0.1 mol of sodium hydroxide and 300 ml size of the particles became large, ultrasonic waves of water. To this solution was added 30 g of a 10% poly 65 were applied to the solution. The solution was then coa vinyl alcohol (as described above) acqueous solution. ted on a 50 g/m paper in an amount of 3 g/m on a Then, a solution prepared by dissolving 0.1 mol of zinc solids basis, followed by drying. 3,871,900 11 2 Results of Comparison Test 2 Run Kind Ether Amount Color-developing Color-developing No. Added Ability Toward Ability Toward Crystal Violet 3-N,N-Diethyl Lactone annino-7-N,N- dibenzylamino fluoran

7 Com parative - - 0.753 0.61 Ex. 2 8 Ex. 2 Diethylenc 30 g 0.895 0.713 Glycol Mono Butyl Ether

EXAMPLE 3 15 EXAMPLE 4 0.1 Mol of 3,5-di-tert-butylsalicylic acid was dis 5 Grams of activated clay was dispersed in 50 cc of solved in a mixture of 0.1 mol of sodium hydroxide and water. To this was added 0.6 cc of a 20% sodium hy 300 ml of water. To this solution were added 50 g of a droxide. Then, a solution prepared by dissolving 10 g 10% polyvinyl alcohol (as described in Example 1) of a 10% polyvinyl alcohol (as described in Example 1) aqueous solution, 20 g of agalmatolite and an ether or 20 aqueous solution and 0.012 mol of zinc sulfate in 10 cc alcohol as shown in the following table. Then, a solu of water was gradually added thereto under stirring. tion prepared by dissolving 0.15 mol of zinc chloride in Furthermore, after adding thereto an alcohol given in 1000 ml of water was gradually added thereto under the following table, a solution prepared by dissolving stirring. Furthermore, 50 g of a styrene-butadiene co 0.01 mol of 3,5-di-tert-butylsalicylic acid and 0.01 mol polymer latex was added thereto. The resulting coating 25 of sodium hydroxide in 30 cc of water was gradually solution was applied to a 50 g/m paper in an amount added thereto. After the completion of the addition, 4 of 3 g/m' on a solids basis. The viscosity of the solution g of a styrene-butadiene latex was added thereto to pre was low, and the coating characteristics of the solution pare a coating solution. The resulting coating solution were good. was coated onto a 50 g/m paper in an amount of 3 g/m 30 on a solids basis followed by drying. COMPARATIVE EXAMPLE 3 0.1 Mol of 3,5-di-tert-butysalicylic acid was dissolved COMPARATIVE EXAMPLE 4 in a mixture of 0.1 mol of sodium hydroxide and 300 5 Grams of activated clay was dispersed in 50 cc of ml of water. To this solution were added 50 g of a 10% water. To this was added 0.6 cc of 20% sodium hydrox polyvinyl alcohol (as described in Example 1) aqueous 35 ide. Then, a solution prepared by dissolving 10 g of a solution and 20 g of agalmatolite. Then, a solution pre 10% polyvinyl alcohol (as described in Example 1) pared by dissolving 0.15 mol of zinc chloride in 1000 aqueous solution and 0.012 mol of zinc sulfate in 10 cc ml of water was gradually added thereto under stirring. of water was gradually added thereto under stirring. Furthermore, 50 g of a styrene-butadiene copolymer Furthermore, a solution prepared by dissolving 0.01 latex was added thereto. The resulting coating solution 40 mol of 3,5-di-tert-butyl-salicylic acid and 0.01 mol of was applied to a 50 g/m paper in an amount of 3 g/m sodium hydroxide in 30 cc of water was gradually on a solids basis. The coating solution had a high vis added thereto under stirring. After the completion of cosity and contained many bubbles, and the particle the addition, 4 g of a styrene-butadiene latex was added size of the metal compound was large. Therefore, the thereto to prepare a coating solution. The resulting solution was coated on the support after applying ultra 45 coating solution was coated on a 50 g/m paper in an sonic waves thereto. amount of 3 g/m on a solids basis followed by drying.

Results of Comparison Test 3

Run Kind Ether or Amount Color-developing Color-developing N. Alcohol Added Ability Toward Ability Toward 3 Crystal Violet N,N- Diethylamino Lactone 7-N,N-dibenzyl aminofluoran

9 Con parative - - ().76 (),655 Ex () Ex 3 sec-Butyl 10 g ().867 O.73 Alcohol Ex. 3 n-Nonyl 10 g ().798 0.677 Alcohol 2 Ex. 3 Ethylene 10 g ().896 0.72 () Glycol Di methyl Ether 3 Ex. 3 Polyoxy- () g ().79) (). 684 ethylene Olcyl Alcohol Fther (22 ethenoxy units) 3,871,900 13 14 Results of Comparison Test 4

Run Kind Alcohol Amount Color-developing Color-develop N. Added Ability Toward ing Ability a Crystal Violet Toward 3-N,N- lactone Diethylamino 7-N,N-dihenzyl amino fuoran 14 Conn parative Ex 4 - 0.745 0.615 5 Ex. 4 n-Butyl Alcohol 0.5g (),852 0.70 6 Ex. 4 do. 2.0 g 0.898 0.78 7 Ex. 4 n-Hexyl Alcohol 0.5g 0.753 0.656 18 Ex. 4 Diacetone Alcohol t.0 g 0.887 0.71 19 Ex. 4 n-Octyl Alcohol 0.5 g. 0.766 0.662 2) Fx 4. do. 3.0 g 0.895 0.720

Additionally, the coating solution of the present in- EXAMPLE 6 vention was low in viscosity and the particle size of the metal salt of the aromatic carboxylic acid formed by The procedures described in Example 1 were re the reaction was small. In addition, water-immersion peated except for adding 2 g of diethylene glycol mono coloration was particularly small when n-octyl alcohol 25 butyl ether and 0.5g of n-octyl alcohol in place of 3 g or n-hexyl alcohol was used. However, n-butyl alcohol of diethylene glycol monobutyl ether. Thus, there were and diacetone alcohol also provided sufficient effects. obtained the following results. EXAMPLE 5 30 Color-developing Ability Color-developing Ability 5 Grams of kaolin was dispersed in 50 cc of water. To Toward Crystal Violet Toward 3-N,N-Diethylamino this was added under stirring a solution prepared by lactone 7-N,N-dibenzylaminofluoran dissolving 10 g of a 5% hydroxymethyl cellulose and 0.01 mol of tin sulfate in 10 cc of water. Furthermore, 0,900 ().723 after adding thereto 3g of diethylene glycol monobutyl 35 ether, a solution prepared by dissolving 0.01 mol of Also, the water-immersion coloration was sufficiently 3,5-di-tert-amylsalicylic acid and 0.01 mol of potas low. Thus, the resulting sheet was found to be a practi sium hydroxide in 30 cc of water was gradually added cal recording sheet. thereto under stirring. After the completion of the ad From the results of the above-described test, it has dition, 3 g of a vinyl acetate-acrylate copolymer was 40 been found that the color-developing ability toward added thereto to prepare a coating solution. The result crystal violet lactone and 3-N,N-diethylamino-7-N,N- ing coating solution was applied to a 50 g/m paper in dibenzylaminofluoran is markedly improved by adding an amount of 4 g/m as solids, followed by drying. at least one of an ether or alcohol to a color developer layer containing a metal compound of an aromatic car COMPARATIVE EXAMPLE 5 45 boxylic acid. Similar effects also were observed with 5 Grams of kaolin was dispersed in 50 cc of water. To respect to other color formers. this was added under stirring a solution prepared by The step for preparing a coating solution was simpli dissolving 10 g of 5% hydroxymethyl cellulose and 0.01 fied and, in addition, the viscosity of the coating solu mol of tin sulfate in 10 cc of water. Furthermore, 0.01 tion was so low that the coating solution had excellent mol of 3,5-di-tert-amylsalicylic acid and 0.01 mol of 50 coating characteristics. potassium hydroxide were dissolved in 30 cc of water The water-immersion coloration was also remarkably and gradually added thereto. After the completion of depressed and the commercial value of the resulting the addition, 4.3 g of vinyl acetate-acrylate (1:1 molar sheet was markedly improved. Additionally, the light ratio) copolymer was added thereto to prepare a coat fastness, and water resistance of the color image, the ing solution. The resulting coating solution was applied 55 activity of the color developer sheet with the passage to a 50 g/m paper in an amount of 4 g/m' on a solids of time, and the like were not affected at all. basis, followed by drying. While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various Results of Comparison Test 5 60 changes and modifications can be made therein with out departing from the spirit and scope thereof. Run Kind Color-developing Color-developing N). Ability Toward Ability Toward What is claimed is: Crystal Violet 3-N,N-Diethylamino 1. A recording sheet comprising a support having Lactone N,N-dibenzylamino thereon a color developer layer capable of reacting fluoran 65 with a color former to form color images, said color de 21 Comparative ().75() ().618 veloper layer containing (1) a metal salt of an aromatic Example 5 carboxylic acid and (2) at least one member selected 22 Example 5 0.902 0.727 from the group consisting of ethers and alcohols, said 3,871,900 15 16 component (1) and said component (2) being present 8. The recording sheet of claim 1, wherein said color at a proportion sufficient to increase the color developer layer contains from 10 to 250 parts by developing ability of said color developer and said weight of said ether and alcohol per 100 parts by color former. s: weight of said aromatic carboxylic acid and wherein 2. The recording sheet of claim 1, wherein said metal 5 said color developer layer is present on said support a of said metal salt of an aromatic carboxylic acid is a level of at least 0.1 g/m as the metal salt of the aro member of Group I B, Group II A, Group II B, Group matic carboxylic acid. III B, Group IV A, Group VI A, Group VII B or Group 9. The recording sheet of claim 1, wherein said ether VIII of the Periodic Table. is represented by the formula: 3. The recording sheet of claim 1, wherein said aro 10 matic carboxylic acid is represented by the formula: ROX

COOH 21 (R) O (R) N

wherein R may be the same or different and represents wherein X is -(CH2)OR', -(CH),OH, -(CH. a hydrogen atom, a hydroxy group, a halogen atom, a 25 ),OH, -(CH2)OR', an alkyl group having up to nitro group, an alkyl group having 1 to 10 carbon 8 carbon atoms or an alkenyl group having up to 18 atoms, the total carbon number in the R's being less carbon atoms, R is an alkyl group having up to 10 car than 13, an aryl group, an arylamino group or an alicy bon atoms, an aryl group having up to 10 carbon atoms clic group, m is an integer of 0 to 7 and n is an integer 30 or an alkenyl group having up to 10 carbon atoms, R' of 0 to 5, or said aromatic carboxylic acid may be di and R' each is an alkyl group having up to 18 carbon merized through the substituent R as a methylene atoms, an aryl group having up to 18 carbon atoms or group. an alkenyl group having up to 18 carbon atoms, p is an 4. The recording sheet of claim 3, wherein said metal integer of 1 to 20 and q is an integer of 2 to 30. of said metal salt of an aromatic carboxylic acid is a 35 10. The recording sheet of claim 1 wherein said alco member of Group I B, Group II A, Group II B, Group hol is an aliphatic alcohol having 1 to 18 carbon atoms. III B, Group IV A, Group VI A, Group VII B or Group 11. The recording sheet of claim 1 wherein said alco VIII of the Periodic Table; hol is selected from the group consisting of n-butyl al wherein said color developer layer contains from 10 cohol, n-amyl alcohol, n-hexyl alcohol, n-heptyl alco to 250 parts by weight of said ether and alcohol per 40 hol, n-octyl alcohol, n-nonyl alcohol, n-decyl alcohol, 100 parts by weight of said aromatic carboxylic lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl acid and wherein said color developer layer is pres alcohol, isobutyl alcohol, sec-butyl alcohol, isoamyl al ent on said support at a level of at least 0.1 g/m' as cohol, tert-butyl alcohol, sec-butyl carbinol, diethyl the metal salt of the aromatic carboxylic acid; carbinol, 1-hexanol, 2-hexanol, 3-hexanol, cyclohexa said ether is represented by the formula: 45 nol, 3-methyl-1-pentanol, 4-methyl-2-hexanol, allyl al cohol, trans-crotyl alcohol, ciscrotyl alcohol, ROX 2-methyl-3-buten-1-ol, o-tolyl carbinol m-tolyl carbi wherein X is -(CH)OR', -(CH2)OH, -(CH nol, p-tolyl carbinol and benzyl alcohol. ),OH, - (CH), OR', an alkyl group having 12. The recording sheet of claim 1 wherein said aro up to 18 carbon atoms or an alkenyl group having 50 matic carboxylic acid is selected from the group con up to 18 carbon atoms, R is an alkyl group having sisting of benzoic acid, nitrobenzoic acid, chloroben up to 10 carbon atoms, an aryl group having up to zoic acid, toluic acid, 4-methyl-3-nitrobenzoic acid, 2 10 carbon atoms or an alkenyl group having up to chloro-4-nitrobenzoic acid, 2,3-dichlorobenzoic acid, 10 carbon atoms, R' and R' each is an alkyl group 4-methyl-3-nitrobenzoic acid, 4-acetylbenzoic acid, having up to 18 carbon atoms, an aryl group having 55 2,4-dihydroxybenzoic acid, 2,5-dihydroxybenzoic acid, up to 8 carbon atoms or an alkenyl group having 1-napththoic acid, 2-naphthoic acid, 1-hydroxy-2- up to 18 carbon atoms, p is an integer of 1 to 20 naphthoic acid, 2-hydroxy-3-naphthoic acid, 2 and q is an integer of 2 to 30; and hydroxy-1-naphthoic acid, thiosalicyclic acid, salicylic the alcohol is an aliphatic alcohol having from 1 to 60 acid, 3,5-dinitrosalicylic acid, 3-methylsalicyclic acid, 18 carbon atoms. 2,4-cresotinic acid, 2,5-cresotinic acid, 3 5. The recording sheet of claim 1, wherein said ether methylsalicyclic acid, 2,4-cresotinic acid, 2,5- is a glycol ether. cresotinic acid, 5-tert-butylsalicylic acid, 3 6. The recording sheet of claim , wherein said alco phenylsalicylic acid, 3-methyl-5-tert-butylsalicylic hol is an alcohol having 4 or more carbon atoms. 65 acid, 3,5-di-tert-butylsalicylic acid, 3,5-di-tert 7. The recording sheet of claim 1, wherein said color amylsalicylic acid, 3-cyclohexylsalicylic acid, developer layer contains a mixture of at least on ether 5-cyclohexylsalicylic acid and 3-methyl-5- and at least on alcohol. isoamylsalicylic acid. 3,871,900 17 8 13. The recording sheet of claim i, wherein said Group II B, Group III B, Group IV A, Group VI A, metal salt of said aromatic carboxylic acid is a copper, Group VII B or Group VIII of the Periodic Table. zinc, aluminum, tin or nickel salt. 17. A pressure sensitive copying assembly comprising 14. A pressure sensitive copying assembly comprising a color former layer and a color developer layer carried a color former layer on a first support and a color de on the same support, said color developer layer and veloper layer on a second support, said color developer said color former layer being in relationship such that layer and said color former layer being brought to at the time of pressure sensitive copying, color devel gether at the time of pressure sensitive copying to per oper and color former are brought into reactive contact mit color developer and color former to be brought to form a color image. Said color developer layer con into reactive contact to form a color image, said color O taining (1) a metal salt of an aromatic carboxylic acid developer layer containing (1) a metal salt of an aro and (2) at least one member selected from the group matic carboxylic acid and (2) at least one member se consisting of ethers and alcohols, said component (1) lected from the group consisting of ethers and alcohols, and said component (2) being present at a proportion said component (l) and said component (2) being sufficient to increase the color-developing ability of present at a porportion sufficient to increase the color 15 said color developer and said color former. developing ability of said color developer and said 18. The pressure sensitive copying assembly of claim color former, 17 wherein said color developer layer contains from 10 15. The pressure sensitive copying assembly of claim to 250 parts by weight of said ether and alcohol per 100 14 wherein said color developer layer contains from 10 parts by weight of said aromatic carboxylic acid and to 250 parts by weight of said ether and alcohol per 100 wherein said color developer layer is present on said parts by weight of said aromatic carboxylic acid and Support at a level of at least 0.1 g/m as the metal salt wherein said color developer layer is present on said of the aromatic carboxylic acid. support at a level of at least 0.1 g/m' as the metal salt 19. The pressure sensitive copying assembly of claim of the aromatic carboxylic acid. 18, wherein said metal of said metal salt of an aromatic 16. The pressure sensitive copying assembly of claim 25 carboxylic acid is a member of Group I B, Group II A, 15, wherein said metal of said metal salt of an aromatic Group II B, Group III B, Group IV A, Group VI A, carboxylic acid is a member of Group I B, Group II A, Group VII B or Group VIII of the Periodic Table. ck :k k sk sk

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